There’s a lot of talk about this year’s flu season and how it’s earlier/worse than usual (as you can see from the graph above). So we thought we’d answer the question: do cattle get the flu?
A plethora of respiratory viruses
There’s lots of viruses that can affect the respiratory system of birds and mammals. While cows and calves can get viral respiratory infections, technically they’re not influenza (a.k.a. the “flu”). Influenza is an Orthomyxovirus, while the viruses affecting cattle – IBR, PI and BRSV – fall into the Herpesvirus and Paramyxovirus families.
While cattle don’t get the flu, other animals do. An outbreak of equine influenza into Australia 12 years ago caused significant issues in the industry (you may remember that the horse events weren’t run at that year’s Heytesbury Show).
Avian influenza is another important disease that the Australian poultry industry is always on the alert for. Avian influenza often makes the news as it crosses the species barrier and can cause disease (and death) in humans.
How do respiratory viruses spread and cause disease?
This is where human flu and cow coughs are similar. They spread in the same way, through breathing in infected aerosols from coughing or sneezing carrier and clinically affected animals.
The respiratory system has several defences to keep viruses and bacteria at bay. Tiny hairs in the nasal passages sieve out dust and bacteria and humidify the inhaled air. These hairs can be damaged by high levels of ammonia, dust, dehydration and temperature and humidity extremes.
More tiny hairs (called cilia) in the trachea push any bacteria up and away to be swallowed. In the lungs, antibodies attach to bacteria and viruses and then white blood cells come along and engulf and destroy them. Inadequate colostral antibodies will mean calves are less able to fight off infections.
Viruses infect the nasal cavity and upper respiratory tract leading to nasal discharge, conjunctivitis and coughing. The viruses can also destroy the cilia lining the trachea while co-infection with Pestivirus also impairs the immune system. Once the defences are down, the lungs can be colonised – which can lead to nasty bacterial infections. The clinical signs are more severe, such as fever, breathing difficulties and even death.
Reducing the risk of respiratory disease
Preventing disease is all about reducing exposure to bacteria and viruses and maximising the immune system. For example, in calves it involves lowering stocking rates, ensuring adequate colostral antibodies, improving calf shed air quality, minimising draughts, isolating sick animals and ensuring they get lots of TLC.
Look after yourselves too!
It’s easy to get run down in the cold and wet of winter but catching the flu is an added hassle that no one wants. The Health Direct website has lots of information and graphics that you might find useful.